Different Routes for Amination of Platinum(II)-Bound Cyanoguanidine

The consecutive addition of AgSO3CF3 (1 or 2 equiv) and cyanoguanidine (1 or 2 equiv, respectively) to the platinum(II) precursor [PtI2(tmeda)] leads to the cis-[PtI(tmeda){NCNC(NH2)2}](SO3CF3) (1·(SO3CF3)) or cis-[Pt(tmeda){NCNC(NH2)2}2](SO3CF3)2 (2·(SO3CF3)2) complexes. The reaction between 1·(SO3CF3) or 2·(SO3CF3)2 and the excess of R2NH (R = H, R2 = C5H10) in EtOH gives the triazapentadiene compounds cis-[Pt(tmeda){NHC(NR2)NC(NH2)NH}](SO3CF3) (3·(SO3CF3) and 4·(SO3CF3), correspondingly). Protonation of these species results in cis-[Pt(tmeda){NHC(NR2)NHC(NH2)NH}](SO3CF3)2 ([3·H](SO3CF3)2 and [4·H](SO3CF3)2, respectively). The interaction of solid 2·(SO3CF3)2 and the gaseous RNH2 (R = H, Me) leads to cis-[Pt(tmeda){NHC(NHR)NHC(NH2)NH}2](SO3CF3)2 (5·(SO3CF3)2 and 6·(SO3CF3)2, respectively). Treatment of an acetone solution of 2·(SO3CF3)2 with an aqueous NH3 or the reaction of 5·(SO3CF3)2 with Me2CO produces the triazine complex cis-{Pt(tmeda){NHCNHC(Me)2}NHC(NH)2N}2(SO3CF3)2 (7·(SO3CF3)2). The reaction of 5·(SO3CF3)2 with Me2CO also leads to 7·(SO3CF3)2. All new complexes were characterized by elemental analyses (C, H, N), electrospray ionization mass spectrometry, IR, and 1H and 13C NMR spectroscopies. The structures of 1·(SO3CF3), 2·(SO3CF3)2, 3·(SO3CF3), [4·H](SO3CF3)2, 5·(SO3CF3)2, and 7·(SO3CF3)2 were determined by single-crystal X-ray diffraction.